Electronic component, semiconductor device, methods of manufacturing the same, circuit board, and electronic instrument

ABSTRACT

The present invention is a semiconductor device capable of relieving thermal stress without breaking wire. It comprises a semiconductor chip ( 12 ), a solder ball ( 20 ) for external connection, wiring ( 18 ) for electrically connecting the semiconductor chip ( 12 ) and the solder ball ( 20 ), a stress relieving layer ( 16 ) provided on the semiconductor chip ( 12 ), and a stress transmission portion ( 22 ) for transmitting stress from the solder ball ( 20 ) to the stress relieving layer ( 16 ) in a peripheral position of an electrical connection portion ( 24   a ) of the solder ball ( 20 ) and wiring ( 18 ).

This is a continuation of application Ser. No. 10/331,510 filed Dec. 31,2002, now U.S. Pat. No. 7,235,881 which is a continuation of applicationSer. No. 09/953,858 filed Sep. 18, 2001, now U.S. Pat. No. 6,518,651which is a continuation of application Ser. No. 09/142,856 filed Mar.26, 1999 now U.S. Pat. No. 6,323,542 which is a National Stage ofPCT/JP98/00130 filed Jan. 16, 1998.

TECHNICAL FIELD

The present invention relates to a compact electronic component and asemiconductor device whose final formed package size is close to thesize of the chip (semiconductor element), to methods of manufacturingthese, to a circuit board on which these are mounted, and to anelectronic instrument having this circuit board.

BACKGROUND ART

To pursue high density mounting in semiconductor devices, bare chipmounting is the ideal. However, quality control and handling of barechips are difficult. For this reason, CSP (chip size/scale package)technology, in which the package size is close to the chip size, hasbeen developed.

In such a CSP semiconductor device, an important problem is to relievethe thermal stress due to the differences in coefficient of thermalexpansion between the semiconductor chip and the mounting board. Inparticular, as the number of pins continues to increase, it is essentialthat no wiring breaks are caused by thermal stress, since wiring isrequired to connect from the electrodes to the solder balls.

The present invention addresses the above described problems, and has asits object the provision of an electronic component, a semiconductordevice, methods of manufacturing these, a circuit board on which theseare mounted, and an electronic instrument having this circuit board.

DISCLOSURE OF THE INVENTION

The semiconductor device of the present invention comprises asemiconductor element, an external electrode provided within the regionof the semiconductor element for external connection, wiring connectedthrough a connection portion to the external electrode and electricallyconnecting the semiconductor element and the external electrode, astress relieving portion provided on the semiconductor element, and astress transmission portion transmitting stress from the externalelectrode to the stress relieving portion.

Since the semiconductor element and external electrode of the presentinvention are connected by the wiring, the pitch of external electrodecan be converted as required. The stress transmission portion transmitsstress from the external electrode to the stress relieving portion, andstress can be thus relieved.

The wiring is connected to the external electrode through a connectionportion. The connection portion is not restricted to the case ofexisting as a separate member between the wiring and the externalelectrode, but includes the case of being a part of at least one of thewiring and external electrode. The connection portion is not restrictedto directly contacting at least one of the wiring and externalelectrode, but includes the case of not directly contacting either. Thatis to say, the connection portion of the present invention indicates atleast a part of the member electrically connecting the wiring andexternal electrode.

More specifically, the wiring may be provided on the stress relievingportion, and the stress transmission portion may be provided in theconnection portion.

By this means, since the wiring is provided on the stress relievingportion, the connection portion and stress transmission portion areprovided on the stress relieving portion, and the stress from theexternal electrode is transmitted to the stress relieving portion.

Alternatively, the wiring may be provided under the stress relievingportion, the connection portion may be provided to pass through thestress relieving portion, and the stress transmission portion may beformed on the stress relieving portion integrally with the connectionportion.

By this means, since the connection portion passes through the stressrelieving portion, the connection portion does not transmit stressvertically to the stress relieving portion. In place of this, the stresstransmission portion provided on the stress relieving portion transmitsstress to the stress relieving portion.

The stress relieving portion may be formed with a thickness to reach thestress transmission portion from the wiring.

The stress relieving portion may have a groove formed outside of thestress transmission portion. By forming a groove, the stress relievingportion is more easily deformed, and stress from the stress transmissionportion can be absorbed more easily.

The stress relieving portion may have a space formed between a contactposition on the wiring and a contact position under the stresstransmission portion. By this means, the stress relieving portion ismore easily able to deform, and stress from the stress transmissionportion can be absorbed more easily.

A stress relieving portion having such a space may be formed with athickness to reach the stress transmission portion from the wiring, andthen may be etched from the outside of the stress transmission portionto underneath thereof.

The present invention may further comprise a supplementary transmissionportion provided at least between a root periphery of the externalelectrode and the stress relieving portion, and transmitting stress fromthe external electrode to the stress relieving portion.

By means of the supplementary transmission portion, stress from theexternal electrode is transmitted to the stress relieving portion, and aconcentration of stress between the external electrode and the stresstransmission portion can be prevented.

The supplementary transmission portion may be formed of a materialcapable of being used for the stress relieving portion.

The stress relieving portion may include a first stress relieving layerand a second stress relieving layer formed on the first stress relievinglayer;

the wiring may be provided between the first and second stress relievinglayers;

the connection portion may be provided to penetrate the second stressrelieving layer; and

the stress transmission portion may be formed on the second stressrelieving layer integrally with the connection portion.

By this means, the connection portion transmits stress in the verticaldirection to the first stress relieving layer. Meanwhile, the stresstransmission portion transmits stress to the second stress relievinglayer. In this way, stress is relieved at two locations.

The stress relieving portion may include a first stress relieving layerand a second stress relieving layer formed on the first stress relievinglayer;

the wiring may be provided between the first and second stress relievinglayers;

the connection portion may be provided to penetrate the second stressrelieving layer; and

the stress transmission portion may include a first transmission portionformed between the first and second stress relieving layers integrallywith the connection portion, and a second transmission portion formed onthe second stress relieving layer integrally with the connectionportion.

The connection portion transmits stress in the vertical direction to thefirst stress relieving layer. Stress is also transmitted to the firststress relieving layer from the first transmission portion of the stresstransmission portion. Furthermore, the stress transmission portion has asecond stress transmission portion, and this second stress transmissionportion transmits stress to the second stress relieving layer. In thisway, stress is relieved at three locations.

It is preferable that the second transmission portion has a larger areathan the first transmission portion, and transmits the stress to thesecond stress relieving layer.

Since the second transmission portion transmits a large amount ofstress, the stress transmitted by the first transmission portion iscomparatively small. The first transmission portion is close to thedirect contact portion of the connection portion and wiring. Therefore,by reducing the stress transmitted from the first transmission portion,the effect on this contact portion can be reduced.

It is preferable that the stress transmission portion is providedwithout contacting the connection portion.

By this means, the stress transmission portion does not transfer stressto the direct contact portion of the connection portion and wiring.

The stress relieving portion may have an isolation portion forinhibiting transmission of the stress between a support regionsupporting the stress transmission portion and a connection region inwhich the connection portion is formed.

Because the isolation portion is provided, stress transmitted from thestress transmission portion to the support region of the stressrelieving portion is not transmitted to the connection region.Therefore, transfer of stress from the stress transmission portionthrough the stress relieving portion to the connection portion also doesnot occur.

Here, the isolation portion may for example be a groove.

The wiring preferably has a bent portion forming an empty portion withthe semiconductor element.

By this means, since the wiring can freely deform in the bent portion,maximum stress absorption is possible.

A gel material may be injected in the empty portion to protect the bentportion.

The stress relieving portion may include a first stress relieving layerand a second stress relieving layer formed on the first stress relievinglayer;

the wiring may include a first wiring portion formed below the firststress relieving layer and a second wiring portion formed between thefirst and second stress relieving layers;

the connection portion may include a first wiring connection portionpenetrating the first stress relieving layer and connecting the firstand second wiring portions and a second wiring connection portionpenetrating the second stress relieving layer and connecting theexternal electrode and the second wiring portion;

the first and second wiring connection portions may be disposed ondifferent planes; and

the stress transmission portion may include a first transmission portionformed between the first and second stress relieving layers integrallywith the first wiring connection portion, and a second transmissionportion formed on the second stress relieving layer integrally with thesecond wiring connection portion.

Since the first and second wiring connection portions of the presentinvention are provided with first and second transmission portionsrespectively, in each of the wiring connection portions, stress can betransmitted to the stress relieving layer. The contact position of thefirst wiring connection portion with respect to the first and secondwiring portions, and the contact position of the second wiringconnection portion with respect to the external electrode and secondwiring portion are disposed on different planes. Therefore, stressapplied to one of the contact positions is not directly easilytransferred to the other contact position. Since stress transferred fromthe external electrode is relieved before reaching the semiconductorelement, the effect on this semiconductor element can be reduced.

The wiring may be brought out from the external electrode substantiallyat right angles to a direction of generation of the stress.

By this means, the generating direction of the stress and the extendingdirection of the wiring are substantially orthogonal. Thus theapplication of tension to the wiring in the direction of its extensionand consequent wiring breaks can be prevented.

The stress transmission portion may be formed at a position outside ofthe connection portion.

Since the stress transmission portion is transmitting stress at aperipheral position of the connection portion of the external electrodeand wiring, stress can be transmitted over a large area.

The electronic component of the present invention comprises anelectronic element; an external electrode for external connection;wiring electrically connecting the electronic element and the externalelectrode; a stress relieving portion provided on the electronicelement; and a stress transmission portion transmitting stress from theexternal electrode to the stress relieving portion, at a peripheralposition of an electrical connection portion of the external electrodeand the wiring.

The method of manufacturing an electronic component of the presentinvention comprises:

a step of integrally forming in substrate form a plurality of electronicelement;

a step of forming an electrode on the electronic element in substrateform;

a step of providing a stress relieving portion on the electronic elementin substrate form, avoiding the electrode;

a step of forming wiring from the electrode;

a step of providing a stress transmission portion transmitting stressfrom the external electrode to the stress relieving portion, in aperipheral position of the electrical connection portion of the wiringand external electrode; and

a step of separating the electronic element in substrate form intoindividual elements.

The method of manufacturing a semiconductor device of the presentinvention comprises;

a step of forming an electrode on a wafer;

a step of providing a stress relieving portion on the wafer avoiding theelectrode;

a step of forming wiring from the electrode;

a step of providing a stress transmission portion transmitting stressfrom the external electrode to the stress relieving portion, in aperipheral position of the electrical connection portion of the wiringand external electrode; and

a step of separating the wafer into individual elements.

With an aspect of the present invention, after a stress relieving layer,wiring, and external electrode are formed on the wafer, the wafer is cutup to obtain individual semiconductor devices. Therefore, since theformation of stress relieving layer, wiring, and external electrode canbe carried out simultaneously for a large number of semiconductordevices, the fabrication process can be simplified.

The step of forming a stress relieving portion may be carried out afterthe step of forming wiring; and

a step of forming a groove by etching in the stress relieving portionoutside of the stress transmission portion may be performed before thestep of separating the wafer.

By forming the groove, the stress relieving portion is more easilydeformed, and stress from the stress transmission portion can beabsorbed more easily.

The step of forming the stress relieving portion may be carried outafter the step of forming wiring; and

a step of etching the stress relieving portion to under the stresstransmission portion may be performed before the step of separating thewafer.

By this means, the stress relieving portion has a space formed between acontact position over the wiring and a contact position under the stresstransmission portion. Thus, the stress relieving portion is more easilydeformed, and stress from the stress transmission portion can beabsorbed more easily.

A step of providing a material capable of being used for the stressrelieving portion from over the stress relieving portion to at least aroot periphery of the external electrode, to form a Supplementarytransmission portion, may be performed before the step of separating thewafer.

In this way, when the supplementary transmission portion is formed,stress from the external electrode is transmitted to the stressrelieving portion by means of the supplementary transmission portion,and a concentration of stress between the external electrode and thestress transmission portion can be prevented.

The circuit board of present invention has the above describedsemiconductor device and a substrate on which a desired wiring patternis formed; and external electrodes of the semiconductor device areconnected to the wiring pattern. The electronic instrument of thepresent invention has this circuit board.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a first embodiment of the semiconductor device.

FIG. 2 shows a second embodiment of the semiconductor device.

FIG. 3 shows a third embodiment of the semiconductor device.

FIGS. 4A and 4B shows a fourth embodiment of the semiconductor device.

FIG. 5 shows a fifth embodiment of the semiconductor device.

FIG. 6 shows a sixth embodiment of the semiconductor device.

FIG. 7 shows a seventh embodiment of the semiconductor device.

FIG. 8 shows an eighth embodiment of the semiconductor device.

FIG. 9 shows a ninth embodiment of the semiconductor device.

FIG. 10 shows a tenth embodiment of the semiconductor device.

FIGS. 11A and 11B show an eleventh embodiment of the semiconductordevice.

FIGS. 12A and 12B show a twelfth embodiment of the semiconductor device.

FIG. 13 shows a thirteenth embodiment of the semiconductor device.

FIG. 14 shows a fourteenth embodiment of the semiconductor device.

FIG. 15 shows a fifteenth embodiment of the semiconductor device.

FIG. 16 shows a sixteenth embodiment of the semiconductor device.

FIGS. 17A to 17E show a process of fabricating the semiconductor deviceof the present invention.

FIGS. 18A to 18C show a process of fabricating the semiconductor deviceof the present invention.

FIG. 19 shows a CSP semiconductor device.

FIG. 20 shows a circuit board mounted with a semiconductor devicefabricated by application of the method of the present invention.

FIG. 21 snows an electronic instrument equipped with a circuit boardmounted with a semiconductor device fabricated by application of themethod of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments of the present invention is now described withreference to the drawings. The present invention can be applied to acompact electronic component, in particular the examples described areof application to a semiconductor device.

Some of the drawings are enlarged for clarity. In particular thefollowing explanation is in terms of a final separated individualsemiconductor device, and therefore the terminology used, forms, and soforth, may be slightly different from in actual practice. Where asemiconductor chip is referred to, this may refer not only to a singleseparated device (that is, a chip) but also to devices in the form of awafer. In other words, the term “semiconductor chip” used here refers toa certain circuit formed on a base substrate (for example of silicon)and capable of being used once separated, and is not restricted inrespect of whether separated or whether still integral. Furthermore,references are restricted to typical locations where explanation isrequired such as wiring, and therefore in the figures where otherlocations are similar, or other constructions, are omitted.

FIRST EMBODIMENT

FIG. 1 is a sectional view showing a first embodiment of thesemiconductor device. A semiconductor device 10 shown in this figurecomprises a stress relieving layer 16 and wiring 18 formed thereon Inmore detail, on a semiconductor chip 12, a stress relieving layer 16 isformed to avoid an electrode 14, and wiring 18 is formed from theelectrode 14 over the stress relieving layer 16.

The stress relieving layer 16 is formed from a photosensitive polyimideresin, and when the semiconductor device 10 is mounted on a substrate(not shown in the drawings), relieves the stress created by thedifference in the coefficient of thermal expansion between thesemiconductor chip 12 and the substrate. The polyimide resin isinsulating with respect to the wiring 18, is able to protect the surfacea and has heat resistance when a solder ball 20 is melted. A polyimideresin with a low Young's modulus (such as an olefin polyimide resin orBCB manufactured by the Dow Chemical Corporation) is preferably used,and in particular it is preferable that the Young's modulus be not morethan about 20 kg/mm². The stress relieving layer 16 has a larger stressrelieving effect the thicker it is, but a thickness approximately in therange 1 to 100 μm is preferable. However, when a polyimide resin with aYoung's modulus of approximately 10 kg/mm² is used, a thickness ofapproximately 10 μm will be sufficient.

Alternatively, a material which has a low Young's modulus and iseffective for stress relieving such as, silicone denatured polyimideresin, epoxy resin, or silicone denatured epoxy resin may be used as thestress relieving layer 16. When a nonphotosensitive resin is used, incombination with another resist, a required pattern may be formed by aphoto-etching process.

The wiring 18 is formed of chromium (Cr). Here, chromium (Cr) isselected because of its good adhesion properties to the polyimide resinforming the stress relieving layer 16. Alternatively, when resistance tocracks is considered, ductile metal such as aluminum, aluminum alloyssuch as aluminum-silicon and aluminum-copper, copper alloys, copper, orgold may be used. Besides, when titanium or titanium-tungsten, havingexcellent resistance to moisture is selected, wiring breaks due tocorrosion can be prevented. Titanium is also preferable as it hasfavorable adhesion properties with respect to polyimide. When titaniumis used for the wiring 18, a multi-layer construction of titanium andanother of the above metals may be used. The wiring 18 is formed in afilm by sputtering, plating, a combination thereof, or another method,and is patterned by photoetching.

It should be noted that the above described examples of materials forthe stress relieving layer and wiring may equally be applied in asuitable way to all of the second and subsequent embodiments in the sameway as to the first embodiment.

On the wiring 18, a solder ball (external electrode) 20 is provided. Inmore detail, a stress transmission portion 22 is provided on the wiring18, a base 24 is provided on this stress transmission portion 22, and asolder ball 20 is provided on the seat 24. The stress transmissionportion 22 and base 24 are formed by copper plating, and the solder ball20 is formed of solder of at least a hemispherical ball shape. It shouldbe noted that the stress transmission portion 22 and base 24 arepreferably formed from the same metal as that used for the material ofthe wiring 18.

A characteristic of the present embodiment is that as shown in FIG. 1,the width d of the base portion 24 a of the base 24 on the stresstransmission portion 22 and the width D of the stress transmissionportion 22 satisfy the relation d <D.

In other words, the base portion 24 a of the base 24 forms a part(connection portion) of the element electrically connecting the solderball (external electrode) 20 and the wiring 18, and the stresstransmission portion 22 extends integrally to the peripheral positionthereof. By forming such a stress transmission portion 22, the solderball 20 is supported on the stress relieving layer 16 with a iscomparatively wide width D.

Such the wide stress transmission portion 22 is effective fortransmitting stress. That is to say, for example, when heat is appliedto the substrate and the semiconductor device mounted on the substratebecause of the difference in the coefficient of thermal expansionbetween the mounting board and the semiconductor chip 12, a stress ofbending the semiconductor chip 12 is created. This stress is a forcebending over, with the center of the solder ball 20 as axis. Accordingto the present embodiment, by means of the stress transmission portion22 with the comparatively wide width D, the solder ball 20 is supportedwith respect to the stress relieving layer 16. Therefore, the stresstending to bend over the solder ball 20 is transmitted over a wide areato the stress relieving layer 16, and the stress can be largely absorbedby the stress relieving layer 16.

Besides, with regard to the stress transmission effect, the second andsubsequent embodiments are also similar to that shown in the firstembodiment.

It should be noted that while omitted from the drawings, to preventcorrosion and the like of the wiring a wiring protection layer such assolder resist is preferably provided as the outermost layer.

SECOND EMBODIMENT

FIG. 2 is a sectional view showing a second embodiment of thesemiconductor device. The semiconductor device 30 shown in this figurehas wiring 38 formed beneath a stress relieving layer 36. In moredetail, on a semiconductor chip 32, with an oxide layer (not shown inthe drawings) acting as an insulating layer interposed, wiring 38 isformed from an electrode 34. A stress relieving layer 36 is formed overthis. It should be noted that the wiring 38 is formed of chromium (Cr).

In the stress relieving layer 36, a hole 36 a is formed byphotolithography, so that in the region of this hole 36 a the wiring 38is not covered by the stress relieving layer 36. In other words, thehole 36 a is formed so that the wiring 38 is positioned directly underthe hole 36 a. Then a chromium (Cr) layer 42 and a copper (Cu) layer 44are formed by sputtering applied to the wiring 38 and the innercircumferential surface and opening rim surface forming the hole 36 a.In other words, the chromium (Cr) layer 42 and copper (Cu) layer 44 areformed to pass through the stress relieving layer 36. Moreover, in theopening rim portion, the chromium (Cr) layer 42 and copper (Cu) layer 44are arranged to extend with a comparatively wide width.

On the copper (Cu) layer 44, a base 46 is formed of copper (Cu), and onthis base 46, a solder ball 40 is formed. The solder ball 40 iselectrically connected to the electrode 34 through the drawn out wiring38, the copper (Cu) layer 44, the chromium (Cr) layer 42 and the base46.

According to the present embodiment, at the opening rim portion of thehole 36 a, stress from the solder ball 40 is transmitted from a stresstransmission portion 48 formed from at least a part of the chromium (Cr)layer 42, copper (Cu) layer 44 and base 46 to the stress relieving layer36.

This stress transmission portion 48 is positioned outside a connectionportion 38 a. The connection portion 38 a is a part of the chromium (Cr)layer 42, and is a part of the member electrically connecting the solderball (external electrode) 40 and wiring 38.

In this example, the stress transmission portion 48 is provided toinclude a flange portion 48 a, in other words, a projecting portion.Therefore, the stress acting to bend over with the center of the solderball 40 as axis can be transmitted over a wide area to the stressrelieving layer 36 by the stress transmission portion 48. The larger thearea of the stress transmission portion 48, the more effective it is.

Besides, according to the present embodiment, since the stresstransmission portion 48 is disposed at a different height from theconnection portion 38 a with respect to the wiring 38, and theconnection portion 38 a and wiring 38 are disposed on a hard oxidelayer, the stress generated is absorbed by the stress relieving layer36. Therefore, stress is less likely to be transmitted to the connectionportion 38 a, and to the wiring 38, and as a result cracks can beprevented.

THIRD EMBODIMENT

FIG. 3 is a sectional view showing a third embodiment of thesemiconductor device. The semiconductor device 31 shown in this figurehas a supplementary transmission layer 33 formed on the stress relievinglayer 36 of the semiconductor device 30 shown in FIG. 2. In the presentembodiment also, the connection portion 38 a is a part of the chromium(Cr) layer 42, and is a part of the member electrically connecting thesolder ball (external electrode) 40 and wiring 38.

The supplementary transmission layer 33 is formed in contact with, atleast, the root periphery of the solder ball 40. Therefore, through thesupplementary transmission layer 33, stress is transmitted from thesolder ball 40 to the stress relieving layer 36. By this means, thestress is dispersed, and between the solder ball 40 and the stresstransmission portion 48, in particular at the connecting portion of thebase 46 with the copper (Cu) layer 44, a concentration of stress isavoided. It should be noted that here, the stress transmission portion48 is formed from at least a part of the chromium (Cr) layer 42, copper(Cu) layer 44 and base 46.

The supplementary transmission layer 33 is constructed of a resincapable of being used for the stress relieving layer 36, and itsthickness is determined by the flexibility (Young's modulus) of theresin itself, and the magnitude of the stress which it is required to betransmitted. More specifically, when a soft resin is used, a largestress transmission is possible by forming the supplementarytransmission layer 33 with greater thickness. Besides, when acomparatively hard resin is used, by forming the supplementarytransmission layer 33 to be thin, excessive stress transmission can beavoided.

The supplementary transmission layer 33 can be formed by spin coatingafter formation of the solder ball 40.

Alternatively, after formation of the stress transmission portion 48(including the base 46), and before forming the solder ball 40, a resinlayer may be formed on the stress relieving layer 36, an opening formedin the resin layer on the stress transmission portion 48, and the solderball 40 provided. In this case, the opening can be formed by theapplication of a photolithography technique, or an etching technique(dry or wet).

These methods are suitable when the supplementary transmission layer 33is formed before cutting the semiconductor device into individualpieces.

FOUR EMBODIMENT

FIGS. 4A and 4B are sectional views showing a fourth embodiment of thesemiconductor device. It should be noted that FIG. 4A is a section alongthe line IV-IV in FIG. 4B. The semiconductor device 37 shown in thesefigures has grooves 35 formed in the stress relieving layer 36 of thesemiconductor device 30 shown in FIG. 2. However, FIGS. 2 and 4A differin the section position. In the present embodiment again, the connectionportion 38 a is a part of the member electrically connecting the solderball (external electrode) 40 and wiring 38 (see FIG. 2).

As shown in FIGS. 4A and 4B, the grooves 35 are formed positioned on theoutside of the stress transmission portion 48 in the stress relievinglayer 36.

By this means, when stress is transmitted from the stress transmissionportion 48 to the stress relieving layer 36, the stress relieving layer36 can more easily deform at a portion closer to the stress transmissionportion 48 than the grooves 35. By means of this, the stress relievinglayer 36 can more easily absorb stress. In particular, by forming thegrooves 35 when the material forming the stress absorption layer 36 hasa low degree of flexibility (high Young's modulus), a stress relievingability equal to that of the case of a material of a high degree offlexibility (low Young's modulus) can be obtained. If a material of ahigh degree of flexibility is used, and then the above described formingis carried out, stress relief can be even more so achieved. The sameeffect can be expected in the fifth and sixth embodiments describedbelow.

Besides, the grooves 35 are formed on the sides in the direction (shownby an arrow in FIG. 4B) in which stress is applied from the stresstransmission portion 48 to the stress relieving layer 36. Therefore, inthe direction in which the stress is applied, the stress relievingability is increased.

It should be noted that the position of formation of the grooves 35 isnot restricted to the positions shown in FIGS. 4A and 4B. For example,the grooves 35 may be formed on sides in a direction other than thedirection (shown by an arrow in FIG. 4B) in which stress is applied fromthe stress transmission portion 48 to the stress relieving layer 36, ormay be formed to surround the stress transmission portion 48.

FIFTH EMBODIMENT

FIG. 5 is a sectional view showing a fifth embodiment of thesemiconductor device. The semiconductor device 39 shown in this figureis one in which the stress relieving layer 36 of the semiconductordevice 30 shown in FIG. 2 is etched.

That is to say, the stress relieving layer 41 of the semiconductordevice 39 is formed to be thinner than the stress relieving layer 36shown in FIG. 2. A space 43 is formed between the contact position belowthe flange 48 a of the stress transmission portion 48 and the contactposition on the wiring 38. In other words, below the flange portion 48 aof the stress transmission portion 48, the stress relieving layer 41forms a neck. This neck portion may have a circular cross-section, ormay equally be formed with a taper.

In the present embodiment too, the connection portion 38 a is part ofthe member electrically connecting the solder ball (external electrode)40 and wiring 38.

In this way, by forming the space 43 below the flange portion 48 a ofthe stress transmission portion 48, the stress relieving layer 41 ismore easily able to deform. By means of this, the stress relieving layer41 is more easily able to absorb stress.

The space 43, can be formed by carrying out isotropic dry etching on thestress relieving layer 36 shown in FIG. 2. More specifically, byisotropic dry etching, the etch rate is approximately equal in thehorizontal direction and the depth direction. As a result, as shown inFIG. 5, it is possible to etch into a necked shape below the flangeportion 48 a of the stress transmission portion 48. By means of this,the space 43 can be formed.

SIXTH EMBODIMENT

FIG. 6 is a sectional view showing a sixth embodiment of thesemiconductor device. The semiconductor device 45 shown in this figurehas a supplementary transmission portion 47 added to the semiconductordevice 39 shown in FIG. 5.

That is to say, in FIG. 6, a supplementary transmission portion 47 isformed continuous with the stress relieving layer 41 on the periphery ofthe solder ball 40. The supplementary transmission portion 47 isinterposed at least between the root periphery of the solder ball 40 andthe stress relieving layer 41. By this means, stress applied to thesolder ball 40 can be transmitted through the supplementary transmissionportion 47 to the stress relieving layer 41. Moreover, the stress isdispersed, and concentration of the stress at the connecting area of thesolder ball 40 and stress transmission portion 48 is avoided.

The semiconductor device 45 having a supplementary transmission portion47 of this type can be fabricated by, forming the stress relieving layer36 and supplementary transmission layer 33, as shown in FIG. 3, and thencarrying out etching in the same way as in the fifth embodiment.

In the present embodiment too, the connection portion 38 a is part ofthe member electrically connecting the solder ball (external electrode)40 and wiring 38.

SEVENTH EMBODIMENT

FIG. 7 is a sectional view showing a seventh embodiment of thesemiconductor device. This seventh embodiment has the characteristics ofboth the first and second embodiments.

In this figure, a semiconductor device 50 has wiring 58 formed betweenfirst and second stress relieving layers 56 and 57. In more detail, on asemiconductor chip 52, a first stress relieving layer 56 is formed toavoid an electrode 54, and wiring 58 is formed from the electrode 54over the stress relieving layer 56. This structure is the same as in thefirst embodiment.

Over the wiring 58, a second stress relieving layer 57 is formed. Thesecond stress relieving layer 57 may also be provided with a thicknessin a range similar to that of the above described first stress relievinglayer 56. In this stress relieving layer 57, a hole 57 a is formed. Achromium (Cr) layer 62 and a copper (Cu) layer 64 are formed to passthrough the stress relieving layer 57. Alternatively, in place of these,the wiring 18 described in the first embodiment may be used. At openingrim portion of the hole 57 a, and the chromium (Cr) layer 62 and copper(Cu) layer 64 are arranged to broaden with comparatively wide range. Onthe copper (Cu) layer 64 a base 66 is formed, and a solder ball 60 isformed on this base 66.

In the opening rim portion of the hole 57 a, stress from the solder ball60 is transmitted from a stress transmission portion 68 formed by thechromium (Cr) layer 62, copper (Cu) layer 64, and a part of base 66, tothe second stress relieving layer 57. The stress transmission portion 68is provided outside the connection portion 58 a. Here, the connectionportion 58 a is part of the chromium (Cr) layer 62, and is part of themember electrically connecting the solder ball (external electrode) 60and wiring 58.

The structure above the wiring 58 is the same as in the secondembodiment, and detailed description is omitted.

According to the present embodiment, stress in the vertical directionfrom the solder ball 60 is transmitted through the connection portion 58a to the first stress relieving layer 56 and absorbed, while beingtransmitted through the stress transmission portion 68 to the secondstress relieving layer 57 and absorbed. In this way, a two-stageabsorbing structure is provided, whereby the stress absorption is evenmore effective. It should be noted that in the present embodiment, thesecond stress relieving layer 57 also serves as a protecting layer forthe wiring 58 and semiconductor chip 52.

It should be noted that the second stress relieving layer 57 of thepresent embodiment may also have the grooves 35, the necked form of thestress relieving layer 41, or the supplementary transmission portion 47of the fourth to sixth embodiments.

EIGHTH EMBODIMENT

FIG. 8 is a sectional view showing an eighth embodiment of thesemiconductor device. The semiconductor device 51 shown in this figurehas a supplementary transmission layer 53 formed on the first stressrelieving layer 57 of the semiconductor device 50 shown in FIG. 7. Inthe present embodiment too, the connection portion 58 a is part of themember electrically connecting the solder ball (external electrode) 60and the wiring 58.

The supplementary transmission layer 53 is formed at least contactingthe root periphery of the solder ball 60. Therefore, through thesupplementary transmission layer 53, stress is transmitted from thesolder ball 60 to the stress relieving layer 57. By this means, stressis dispersed, and a concentration of stress at the connecting portion ofthe solder ball 60 and the stress transmission portion 68 is avoided.

It should be noted that the material and method of formation of thesupplementary transmission layer 53 is the same as in the thirdembodiment, and description is omitted.

NINTH EMBODIMENT

FIG. 9 is a sectional view showing a ninth embodiment of thesemiconductor device. The ninth embodiment is a modification of theseventh embodiment.

In this figure, a semiconductor device 70 has wiring 78 formed betweenfirst and second stress relieving layers 76 and 77. In more detail, afirst stress relieving layer 76 is formed on the semiconductor chip 72,avoiding an electrode 74. Wiring 78 is formed from the electrode 74 overthe stress relieving layer 76.

On the wiring 78, a second stress relieving layer 77 is formed. To passthrough this stress relieving layer 77, a copper (Cu) layer 82 is formedby sputtering, a copper (Cu) layer 84 is formed by plating, a copper(Cu) layer 86 is formed by sputtering, and a base 88 is formed byplating. A solder ball 80 is formed an this base 88.

Here, the copper (Cu) layer 82 and copper (Cu) layer 84 have a largerarea than the base 88 and base portion 88 a of the copper (Cu) layer 86.In the copper (Cu) layer 82 and copper (Cu) layer 84, a stresstransmission portion 89 corresponding to the position of the peripheryof the base portion 88 a transmits stress from the solder ball 80 to thefirst stress relieving layer 76. It should be noted that a portion ofthe stress transmission portion 89 (the portion contacting the baseportion 88 a) forms a part (connection portion) of the memberelectrically connecting the solder ball (external electrode) 80 andwiring 78.

According to the present embodiment, since the stress transmissionportion 89 is formed positioned on the periphery of the base portion 88a electrically connecting the solder ball 80 and wiring 78, stress canbe transmitted to the first stress relieving layer 76 over a large area.It should be noted that in the present embodiment, even if the firststress relieving layer 76 is omitted, the stress can be absorbed by thesecond stress relieving layer 77.

In the present embodiment too, a stress transmission portion 87 similarto the stress transmission portion 68 of the seventh embodiment (seeFIG. 7) may be further formed, and a similar effect will be obtained.

TENTH EMBODIMENT

FIG. 10 is a sectional view showing a tenth embodiment of thesemiconductor device. This tenth embodiment is a modification of theninth embodiment. Here, to describe only difference from the ninthembodiment. A copper (Cu) layer 92 and copper (Cu) layer 93 formed onwiring 91 are smaller than a stress transmission portion 94. Therefore,stress tending to bend over a solder ball 95 is transmitted from thestress transmission portion 94, but hard to be transmitted from thecopper (Cu) layer 92 and copper (Cu) layer 93. Moreover, the copper (Cu)layer 92 and copper (Cu) layer 93 do not function as a stresstransmission portion, and therefore stress tends not to be transmittedto wiring 91. By this means, breaks of the wiring 91 can be prevented.

In the present embodiment, a part of the stress transmission portion 94forms a part (connection portion) of the member electrically connectingthe solder ball (external electrode) 95 and wiring 91.

It should be noted that the effect in the ninth embodiment that even ifthe first stress relieving layer 76 is omitted, the stress can beabsorbed by the second stress relieving layer 77 is the same in thetenth embodiment.

ELEVENTH EMBODIMENT

FIGS. 11A and 11B show an eleventh embodiment of the semiconductordevice. It should be noted that FIG. 11B is a plan view seen along lineXI-XI in FIG. 11A.

As shown in these figures, with a semiconductor device 100, a solderball 114 is supported by a stress transmission portion 112 in a positionnot contacting an electrical connection portion 110.

In more detail, on an oxide layer 104 formed on a semiconductor chip102, wiring 106 is formed. The wiring 106 electrically connects a pad106 a positioned in the center of the solder ball with to an electrode108. Moreover, the wiring 106 extends from the pad 106 a in a directionperpendicular to the direction (shown by an arrow in FIG. 11B) of stressgenerated by differences in the coefficient of thermal expansion betweenthe mounting board and the semiconductor device 100. Therefore, even ifstress is applied to the wiring 106, since force is not applied in thedirection of extension in the vicinity of the pad 106 a, wiring breaksare less likely to occur.

On the wiring 106 a stress relieving layer 118 is formed. However, onthe pad 106 a a hole is formed in the stress relieving layer 118, andthe connection portion 110 is formed to electrically connect the pad 106a and solder ball 114. The connection portion 110 forms a part of themember electrically connecting the solder ball (external electrode) 114and wiring 106.

Besides, in a peripheral position of the connection portion 110 and in anoncontact position, between an oxide layer 104 and solder ball 114 aplurality of stress transmission portions 112 are provided. For thisreason, in the stress relieving layer 118 a plurality of holes areformed. It should be noted that the connection portion 110 and stresstransmission portion 112 are form,ed continuously as projectionsprojecting downward from a base 116 which supports the solder ball 114.

The present embodiment has the above described structure, and its effectis now described. In the present embodiment, the solder ball 114 iselectrically connected to the wiring 106 by the connection portion 110in a central position thereof. Then a stress transmission portion 112 isprovided in a peripheral position of the connection portion 110 and in anoncontact position. Therefore, since it is in the noncontact state, theinfluence of the stress transmitted by the stress transmission portion112 tends not to be transmitted to the connection portion 110. Thus,stress is not transmitted to the wiring 106 and wiring breaks can beprevented.

The base 116 partially contacts above the stress relieving layer 118. Inparticular, a contact portion 116 a positioned on the periphery of thestress transmission portion 110 is such as to transmit stress to thestress relieving layer 118 and absorb the same.

TWELFTH EMBODIMENT

FIGS. 12A and 12B show a twelfth embodiment of the semiconductor device.It should be noted that FIG. 12B is a plan view seen along line XII-XIIin FIG. 12A. This twelfth embodiment is a modification of the abovedescribed eleventh embodiment. Here the differences from the eleventhembodiment are described.

In FIGS. 12A and 12B, a semiconductor device 120 has first and secondstress relieving layers 122 and 124. Then wiring 126 is formed on thefirst stress relieving layer 122, and a stress transmission portion 128is formed on the first stress relieving layer 124. Therefore, stressfrom a solder ball 130 is transmitted from the stress transmissionportion 128 to the first stress relieving layer 122, and absorbed. Itshould be noted that with regard to a connection portion 132 formed on apad 126 a, the structure is the same as the connection portion 110 shownin FIG. 11A, and therefore description is omitted. That is to say, theconnection portion 132 forms a part of the element electricallyconnecting the solder ball (external electrode) 130 and wiring 126.

According to the present embodiment, stress is relieved through thestress transmission portion 128 by the first stress relieving layer 122.Therefore, the base 134 has a flange formed in a peripheral position ofthe stress transmission portion 128. The contact portion with the secondstress relieving layer 124 is omitted. However, a contact portion may beprovided in the same way as in the eleventh embodiment.

THIRTEENTH EMBODIMENT

FIG. 13 shows a thirteenth embodiment of the semiconductor device. Thisthirteenth embodiment is a modification of the above described eleventhand twelfth embodiments. In other words, in place of the plurality ofpillar-shaped stress transmission portions 112 shown In FIGS. 11A and11B, the semiconductor device 140 shown in FIG. 13 has a cylindricalstress transmission portion 142. This stress transmission portion 142has a part cut away to allow wiring 144 to be led to the inside, and isarranged not to contact the wiring 144. Even with a stress transmissionportion 142 of this type, the same effect as in the eleventh embodimentcan be achieved.

The connection portion electrically connecting the solder ball (externalelectrode) and wiring is the same as in the twelfth embodiment.

FOURTEENTH EMBODIMENT

FIG. 14 shows a fourteenth embodiment of the semiconductor device. Thesemiconductor device 150 shown in this figure also has a first stressrelieving layer 154 formed on a semiconductor chip 152. However, in thisstress relieving layer 154 a substantially circular groove 156 isformed. Thus an island portion 158 delineated by the groove 156 isformed. Besides, wiring 159 is formed to reach the island portion 158.In more detail, in order to form the wiring 159, the groove 156 isformed in a C-shape.

On the first stress relieving layer 154, a second stress relieving layer160 is formed. In the second stress relieving layer 160, a hole 160 a isformed to extend further outside than the groove 156.

Then on the inner surface and opening rim portion of the hole 160 a, onthe surface 154 a of the first stress relieving layer 154 exposed by thehole 160 a, and on the wiring 159 formed on the island portion 158, abase 162 is provided with a thin metal film interposed by sputtering. Asolder ball 164 is provided on the base 162.

According to the present embodiment, island portion 158 is isolated fromthe region receiving stress from the solder ball 164, by means of thegroove 156. Therefore, stress tends not to be transmitted to the wiring159, and the occurrence of wiring breaks can be prevented.

It should be noted that the connection portion being one part of themember electrically connecting the solder ball (external electrode) andwiring is the same as in the twelfth embodiment.

FIFTEENTH EMBODIMENT

FIG. 15 shows a fifteenth embodiment of the semiconductor device. Thesemiconductor device 170 shown in this figure has a bump 174 provided ona stress relieving layer 172 to absorb stress. It is the same as theabove embodiments from the point of view of stress absorption.

The characteristic of the present embodiment is that wiring 176 has abent portion 180 forming an empty portion between the wiring 176 and thesemiconductor chip 178, and the empty portion is injected with a gelmaterial 182. It should be noted that since the gel material 182 isinserted for the purpose of reinforcement, it may be omitted. Besides,the wiring 176 is preferably formed of metal from the viewpoint ofductility. In this way, when the bent portion 180 is formed, even ifstress is applied to the wiring 176, it is absorbed by the bent portion180. Therefore, stress transmitted from the bump 174 is not transmittedto the electrode 184. In this way wiring breaks can be prevented.

To form the bent portion 180 a resist is deposited to outline the bentportion 180, and the wiring 176 is formed thereon, then the resist isremoved by dry etching or wet etching. It should be noted that amaterial other than resist can be used as long as it can be etched.

While omitted from the drawings, a wiring protection layer being asolder resist or the like is preferably provided as the outermost layerto prevent corrosion and the like of the wiring.

The present embodiment can be applied to other embodiments, and in thiscase the connection portion being one part of the member electricallyconnecting the solder ball (external electrode) and wiring is the sameas in the twelfth embodiment.

SIXTEENTH EMBODIMENT

FIG. 16 shows a sixteenth embodiment of the semiconductor device. Thesemiconductor device 190 shown in this figure has first wiring 194formed on a semiconductor chip 192, a first stress relieving layer 196formed on this wiring 194, and second wiring 198 formed on this stressrelieving layer 196.

In more detail, on the first wiring 194, a hole is formed in the firststress relieving layer 196, and the second wiring 198 is formed from thefirst wiring 194 over the first stress relieving layer 196.

On the second wiring 198, a copper (Cu) layer 200 is formed by plating,and on this copper (Cu) layer 200, a second stress relieving layer 202is formed. In the second stress relieving layer 202, a hole 202 a isformed over the copper (Cu) layer 200. A bump 204 is provided on thecopper (Cu) layer 200. Part of the bump 204 contacts the second stressrelieving layer 202, and is arranged to transmit stress.

According to the present embodiment, the connection portion 206 of thefirst and second wiring 194 and 198 and the connection portion 208 ofthe second wiring 198 and the bump 204 are disposed on the differentplanes. Here, the connection portion 206 indicates the portion ofcontact between the first and second wiring 194 and 198, and theconnection portion 208 indicates the portion of contact between thesecond wiring 198 and the bump 204. The connection portions 206 and 208form a part of the member electrically connecting the wiring 194 andbump (external electrode) 204.

Therefore, even if stress is transmitted from the bump 204 through theconnection portion 208 to the second wiring 198, this stress tends notto be transmitted to the other connection portion 206. In this way,since stress is made less likely to be transmitted to the first wiring194, wiring breaks in this wiring 194 are prevented.

(Fabrication Process)

FIGS. 17A to 18C show a manufacturing method of a semiconductor deviceof the present embodiment.

First, using well-known technology, normally, an electrode 302 and otherelements are formed up to the state before carrying out dicing on awafer 300 (see FIG. 17A). In the present embodiment, the electrode 302is formed of aluminum, but equally an aluminum alloy material (forexample, aluminum silicon, aluminum silicon copper, and so on) or acopper material may be used.

On the surface of the wafer 300, a passivation film (not shown in thedrawings) such as an oxide layer is formed to prevent chemical change.The passivation film is formed to avoid not only the electrode 302, butalso a scribing line used to carry out dicing. By not forming thepassivation film on the scribing line, during dicing the creation ofdebris from the passivation film can be avoided, and furthermore, thegeneration of cracks in the passivation film can be prevented.

Next, sputtering is carried out with the wafer 300 as the target, andthe foreign objects are removed from the surface of the wafer 300 (inother words, reverse sputtering).

Then, as shown in FIG. 17A, by means of sputtering a titanium tungsten(TiW) layer 304 and copper (Cu) layer 306 are superimposed on thesurface of the wafer 300. It should be noted that in this fabricationprocess, the example described has titanium tungsten (TiW) and copper(Cu) used for the wiring, but the present invention is not limited tothis.

Then, when the wiring resistance is lowered, in particular on the copperlayer 306, a copper plating layer 308 is formed by electroplating. Thelayer thicknesses may be, for example, approximately the followingvalues:

Titanium tungsten layer: 1000 angstroms (10⁻¹⁰ m)

Copper layer: 1000 angstroms (10⁻¹⁰ m)

Copper plating layer: 0.5 to 5 μm

Next, as shown in FIG. 17B, the titanium tungsten layer 304, copperlayer 306, and copper plating layer 308 are dry etched, applyingphotolithography technology, to form wiring 310.

In more detail, a photoresist (not shown in the drawings) is applied onthe copper plating layer 308, and prebaking, exposure and developmentare carried out. Drying and postbaking are carried out after washing.Then dry etching is applied to the copper plating layer 308 and copperlayer 306 for rinsing, and the titanium tungsten layer 304 is dryetched. Next, the photoresist is removed and washing carried out. Inthis way, as shown in FIG. 17B, the wiring 310 is formed.

Next, the wiring 310 is subjected to ashing by an O₂ plasma, then afterwater is removed from the wafer 300, as shown in FIG. 17C, a polyimideresin 312 is applied to the whole surface of the wafer 300. Thepolyimide resin 312 forms a stress relieving layer same as the stressrelieving layer 36 and the like shown in FIG. 2. Here, by means of theashing, the adhesion properties of the wiring 310 and wafer 300 with thepolyimide resin 312 are improved.

For the polyimide resin 312, it is preferable to use one with goodadhesion properties with the passivation film of the wafer 300, a lowYoung's modulus and a low water absorption ratio, and for which a largefilm thickness is possible.

The polyimide resin 312 is now subjected to prebaking, exposure, drying,development, washing, drying and curing processes. In this way, as shownin FIG. 17D, a hole 314 is formed in the polyimide resin 312. Thepolyimide resin 312, while adhered to the wiring 310 and wafer 300, isshrunk by the drying and curing processes, so that the inside of thehole 314 is shaped as a 60 to 70 degree taper. Therefore, it ispreferable that the polyimide resin 312 is selected so that a taper isshaped inside the hole 314.

Next, the surface of the polyimide resin 312 is subjected to ashing byan O₂ plasma, and sputtering is carried out with this polyimide resin312 as the target to remove foreign objects. By means of the ashing, theadhesion properties of the surface of the polyimide resin 312 with ametal film are improved.

Then as shown in FIG. 17E, by sputtering applied to the whole surface ofthe polyimide resin 312, a titanium tungsten (TiW) layer 316 and copper(Cu) layer 318 are formed to be overlaid. Then, a copper plating layer320 is formed on the copper layer 318 by electroplating. It should benoted that in place of the titanium tungsten layer 316, a titanium (Ti)layer may be formed. The layer thicknesses may be, for example,approximately the following values:

Titanium tungsten layer: 1000 angstroms (10⁻¹⁰ m)

Copper layer: 1000 angstroms (10⁻¹⁰ m)

Copper plating layer: 0.5 to 100 μm

Next, a photoresist is applied on the copper plating layer 320, then thecopper plating layer 320 and copper layer 318 are etched afterprebaking, exposure, development, washing, drying and postbaking arecarried out. Then the titanium tungsten layer 316 is etched afterwashing, and the photoresist is removed, and washing is carried out.

In this way, as shown in FIG. 18A, the stress transmission portion 322is formed on the wiring 310. Then ashing is carried out to the stresstransmission portion 322 by an O₂ plasma.

Then as shown in FIG. 18B, a solder paste 324 is disposed on the stresstransmission portion 322. The solder paste 324 can be provided, forexample, by screen printing. Besides, when the particle size of thesolder paste 324 is of the range around 25 to 15 μm, the printing maskwill be easily released. Alternatively, the solder paste 324 may beprovided by a solder plating method.

Next, through a reflow process, the solder paste 324 is melted to form asolder ball 326 by means of surface tension, as shown in FIG. 18C. Thenthe flux is subjected to washing.

According to the above described manufacturing method of a semiconductordevice, almost all steps are completed within the stage of waferprocessing. In other words, the step in which the external terminals forconnection to the mounting board are formed is carried out within thestage of wafer processing, and it is not necessary to carry out theconventional packaging process, that is to say, in which individualsemiconductor chips are handled, and an inner lead bonding process andexternal terminal formation process are carried out for each individualsemiconductor chip. Besides, when the stress relieving layer is formed,a substrate such as a patterned film is not required. For these reasons,a semiconductor device of low cost and high quality can be obtained.

OTHER EMBODIMENTS

The present invention can be applied to a CSP semiconductor device. InFIG. 19 is shown a typical CSP semiconductor device. In this figure, asemiconductor chip 1 has wiring 3 formed extending from electrodes 2toward the center of an active surface 1 a, and an external electrode 5is provided on each wiring 3. All of the external electrodes 5 areprovided on a stress relieving layer 7, so that the stresses can berelieved when mounted on a circuit board (not shown in the drawings).Besides, excluding the region of the external electrodes 5, a solderresist layer 8 is formed as a protective film.

The stress relieving layer 7 is formed at least in the region surroundedby the electrodes 12. It should be noted that the electrodes 2 refer tothe portions connected to the wiring 3. Besides, when the area requiredto form the external electrodes 5 is considered, although not shown inFIG. 19, the stress relieving layer 7 may be provided on the outside ofthe electrodes 2, and the wiring 3 brought around thereon, to providethe external electrodes 5 in the same way.

The electrodes 2 are positioned around the periphery of thesemiconductor chip 1, in an example of the so-called peripheralelectrode type, however, equally an area array type of semiconductorchip in which the electrodes are formed in a region inside the peripheryof the semiconductor chip may be used. In this case, the stressrelieving layer 7 may be formed to avoid at least a portion of theelectrodes 2.

As shown in this drawing, the external electrodes 5 are provided not onthe electrodes 2 of the semiconductor chip 1, but in the active region(the region in which the active elements are formed) of thesemiconductor chip 1. By providing the stress relieving layer 7 in theactive region, and further positioning (bringing in) the wiring 3 withinthe active region, the external electrodes 5 can be provided within theactive region. That is to say, a pitch conversion can be carried out. Asa result, when laying out the external electrodes 5, the interior of theactive region, that is to say, a region of a particular plane can beprovided. Thus the flexibility for positioning the external electrodes 5is greatly increased.

By bending the wiring 3 at the required position, the externalelectrodes 5 can be aligned in a lattice. It should be noted that thisis not an essential construction of the present invention, and thereforethe external electrodes 5 do not necessarily have to be disposed in alattice.

In FIG. 19, at the junction of the electrodes 2 and wiring 3 the size ofthe electrodes 2 and the size of the wiring 3 are such that:

wiring 3<electrodes 2

but it is preferable that:

electrodes 2≦wiring 3

In particular, in the case that:

electrodes 2<wiring 3

not only is the resistance of the wiring 3 reduced, but also, since thestrength is increased, wiring breaks are prevented.

In each of the above described embodiments, in cases where externalstress applied to the solder ball is concentrated in the wiring, thewiring is designed to be curved (or bent) in the planar direction, andin addition to or separate from this, a bent (curved) structure as inthe fifteenth embodiment is adopted to each embodiment, so thatconcentration of stress on the wiring is dispersed.

In such a semiconductor device, almost all steps can be completed withinthe stage of wafer processing. More specifically, a plurality ofelectrodes 2 are formed on the wafer, and a stress relieving layer 7 isdisposed on the wafer avoiding the electrodes 2, and individualsemiconductor devices are cut from the wafer after gone through theprocess of forming wiring 3 from the electrodes 2.

Here, for the formation of the electrodes 2 and wiring 3, for example,sputtering, etching, or other thin metal film forming technology can beapplied. For the formation of the external electrodes 5, a solderplating process can be applied. Furthermore, for the formation andprocessing of the stress relieving layer 7, a photolithography in whicha photosensitive resin is exposed and developed can be applied. Thesesteps can all be carried out during wafer processing.

In this way, after carrying out almost all of the steps is in waferprocessing, the individual semiconductor devices are cut. By doing thisthe stress relieving layer 7, wiring 3, and external electrodes 5 of aplurality of semiconductor devices can be formed simultaneously. As aresult, the fabrication process can be simplified.

In FIG. 20 is shown a circuit board 1000 on which is mounted asemiconductor device 1100 fabricated by the method of the abovedescribed embodiment. The circuit board generally uses an organiccompound substrate such as glass epoxy. A wiring pattern of, forexample, copper is formed on the circuit board to form a desiredcircuit. The electrical connection Is achieved by mechanical connectionof the wiring pattern and the external terminals of the semiconductordevice. In this case, since the above described semiconductor device hasa construction for absorbing strain generated by differences in thermalexpansion with the exterior provided by the stress relieving portion,when this semiconductor device is mounted on the circuit board andthereafter, the reliability can be improved. Besides, if appropriateattention is paid to the wiring of the semiconductor device, thereliability during connection and the reliability after connection canbe improved. It should be noted that the mounting area can also bereduced to the area for mounting as a bare chip. Therefore, when thiscircuit board is used in an electronic instrument, the electronicinstrument itself can be made more, compact. Besides, within the samearea, greater effective mounting space can be made available, and it ispossible to design for greater functionality.

Next, as an electronic instrument provided with this circuit board 1000,FIG. 21 shows a notebook personal computer 1200.

It should be noted that the above described embodiments apply thepresent invention to a semiconductor device, but the present inventioncan be applied to any surface-mounted electronic component, whetheractive or passive. Electronic components include, for example,resistors, capacitors, coils, oscillators, filters, temperature sensors,thermistors, varistors, variable resistors, and fuses. In addition, byusing given electronic element in place of the semiconductor element inthe above described embodiments, and by forming the same kind of stresstransmission portion as in the above described embodiments, stress canbe relieved by the stress relieving portion, and wiring breaks and thelike can be prevented. Since the manufacturing method is the same as inthe above described embodiment, description is omitted.

1. An electronic component comprising: a base substrate; an electrodethat is disposed on a first surface of the base substrate; a first resinlayer that is formed on or above the base substrate; a wiring that iselectrically connected to the electrode, the wiring being disposed onthe first resin layer; a second resin layer that is formed over the basesubstrate and the wiring, the second resin layer having an opening, theopening being filled with a conductive material electrically connectedto the wiring; and an external terminal that is provided on theconductive material, the external terminal electrically connected to thewiring via the conductive material, a material of the external terminalbeing different from a material of the conductive material, wherein aportion of the wiring between the electrode and the external terminalextends in a direction that changes in a plane parallel to the surfaceof the base substrate.
 2. The electronic component according to claim 1,further comprising a third resin layer formed on the second resin layer,the third resin layer provided around the external terminal.
 3. Theelectronic component according to claim 1, the second resin layer havinga Young's modulus of less than 20 kg/mm².
 4. The electronic componentaccording to claim 1, the second resin layer being formed from amaterial selected from the group consisting of polyimide resin, siliconedenatured polyimide resin, epoxy resin and silicone denatured epoxyresin.
 5. The electronic component according to claim 1, the wiringbeing formed from at least one material selected from the groupconsisting of chromium, aluminum, aluminum alloys, copper, copperalloys, gold, titanium and titanium-tungsten.
 6. A circuit board,comprising: the electronic component according to claim 1; and asubstrate on which a second wiring pattern is formed, wherein theexternal terminal is connected to the second wiring pattern.
 7. Anelectronic instrument having the electronic component according toclaim
 1. 8. A semiconductor device comprising: a semiconductor chip; anelectrode that is disposed on a first surface of the semiconductor chip;a first resin layer that is formed on or above the semiconductor chip; awiring that is electrically connected to the electrode, the wiring beingdisposed on the first resin layer; a second resin layer that is formedover the semiconductor chip and the wiring, the second resin layerhaving an opening, the opening being filled with a conductive materialelectrically connected to the wiring; and an external terminal providedon the conductive material, the external terminal electrically connectedto the wiring via the conductive material, a material of the externalterminal being different from a material of the conductive material,wherein a portion of the wiring between the electrode and the externalterminal extends in a direction that changes in a plane parallel to thesurface of the semiconductor chip.
 9. The semiconductor device accordingto claim 8, further comprising a third resin layer formed over thesecond resin layer, the third resin layer provided around the externalterminal.
 10. The semiconductor device according to claim 8, the secondresin layer having a Young's modulus of less than 20 kg/mm².
 11. Thesemiconductor device according to claim 8, the second resin layer beingformed from a material selected from the group consisting of polyimideresin, silicone denatured polyimide resin, epoxy resin and siliconedenatured epoxy resin.
 12. The semiconductor device according to claim8, the wiring being formed from at least one material selected from thegroup consisting of chromium, aluminum, aluminum alloys, copper, copperalloys, gold, titanium and titanium-tungsten.
 13. A circuit board,comprising: the semiconductor device according to claim 8; and asubstrate on which a second wiring pattern is formed, wherein theexternal terminal of the semiconductor device is connected to the secondwiring pattern.
 14. An electronic instrument having the semiconductordevice according to claim 8.